Antioxidant capacity of Colombian seaweeds: 1. Extracts obtained from Gracilaria mammillaris by means of supercritical fluid extraction

Phlorotannin and its Derivatives, a Potential Antiviral Molecule from Brown Seaweeds, an Overview

Research on seaweeds provides a continual discovery of natural bioactive compounds. The review presents new information on studies of the potential and specific antiviral action of phlorotannin and their derivatives from marine brown algae. Phlorotannin is a polyphenolic derivative and a secondary metabolite from marine brown algae which exhibits a high quality of biological properties. Phlorotannin has a variety of biological activities that include antioxidant, anticancer, antiviral, anti-diabetic, anti-allergic, antibacterial, antihypertensive and immune modulating activities. These phlorotannin properties were revealed by various biochemical and cell-based assays in vitro. This distinctive polyphenol from the marine brown algae may be a potential pharmaceutical and nutraceutical compound. In this review, the extraction, quantification, characterization, purification, and biological applications of phlorotannin are discussed, and antiviral potential is described in detail.

Uncovering the Bioactivity of Aurantiochytrium sp.: a Comparison of Extraction Methodologies

Aurantiochytrium sp. is an emerging alternative source of polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA), and squalene, playing an important role in the phasing out of traditional fish sources for these compounds. Novel lipid extraction techniques with a focus on sustainability and low environmental footprint are being developed for this organism, but the exploration of other added-value compounds within it is still very limited. In this work, a combination of novel green extraction techniques (high hydrostatic pressure extraction (HPE) and supercritical fluid extraction (SFE)) and traditional techniques (organic solvent Soxhlet extraction and hydrodistillation (HD)) was used to obtain lipophilic extracts of Aurantiochytrium sp., which were then screened for antioxidant (DPPH radical reduction capacity and ferric-reducing antioxidant potential (FRAP) assays), lipid oxidation protection, antimicrobial, anti-aging enzyme inhibition (collagenase, elastase and hyaluronidase), and anti-inflammatory (inhibition of NO production) activities. The screening revealed promising extracts in nearly all categories of biological activity tested, with only the enzymatic inhibition being low in all extracts. Powerful lipid oxidation protection and anti-inflammatory activity were observed in most SFE samples. Ethanolic HPEs inhibited both lipid oxidation reactions and microbial growth. The HD extract demonstrated high antioxidant, antimicrobial, and anti-inflammatory activities making, it a major contender for further studies aiming at the valorization of Aurantiochytrium sp. Taken together, this study presents compelling evidence of the bioactive potential of Aurantiochytrium sp. and encourages further exploration of its composition and application.

Present and Future of Seaweed Cultivation and Its Applications in Colombia

Colombia has a diverse range of marine ecosystems in the coastal and insular areas of the Caribbean Sea and the Pacific Ocean. Seaweed research has focused mainly on the identification and taxonomic distribution of 628 species identified so far, mainly in the Caribbean Sea. Among the most widely cultivated genera of seaweeds in open-sea pilot systems in Colombia are Hydropuntia, Gracilaria, Hypnea, Kappaphycus, and Eucheuma. These genera have shown low yields as a consequence of high tissue fragility, epiphytism, sedimentation, and nitrogen deficiency. In addition, the evaluation of the biological activity of selected seaweed compounds has advanced considerably, focusing on their composition and their use for direct consumption by humans and animals. Despite the diversity of seaweeds, as well as certain technical and scientific advances, Colombia is still lagging behind other countries in seaweed exploitation, both in Latin America and worldwide. This current status raises the need to increase research, technological (agro-tech) appropriation, and the adoption of effective public policies that will boost algal businesses. In addition, seaweed cultivation could support the current blue economy transition in Colombia, which could eventually allow the country to enter the global seaweed market.

Bioprospecting macroalgae, marine and terrestrial invertebrates & their associated microbiota

Abstract The present review aims the discussion of the impact of the bioprospection initiative developed by the projects associated to BIOprospecTA, a subprogram of the program BIOTA, supported by FAPESP. This review brings a summary of the main results produced by the projects investigating natural products (NPs) from non-plants organisms, as examples of the success of this initiative, focusing on the progresses achieved by the projects related to NPs from macroalgae, marine invertebrates, arthropods and associated microorganisms. Macroalgae are one of the most studied groups in Brazil with the isolation of many bioactive compounds including lipids, carotenoids, phycocolloids, lectins, mycosporine-like amino acids and halogenated compounds. Marine invertebrates and associated microorganisms have been more systematically studied in the last thirty years, revealing unique compounds, with potent biological activities. The venoms of Hymenopteran insects were also extensively studied, resulting in the identification of hundreds of peptides, which were used to create a chemical library that contributed for the identification of leader models for the development of antifungal, antiparasitic, and anticancer compounds. The built knowledge of Hymenopteran venoms permitted the development of an equine hyperimmune serum anti honeybee venom. Amongst the microorganisms associated with insects the bioprospecting strategy was to understand the molecular basis of intra- and interspecies interactions (Chemical Ecology), translating this knowledge to possible biotechnological applications. The results discussed here reinforce the importance of BIOprospecTA program on the development of research with highly innovative potential in Brazil.

Extraction of Fatty Acids and Phenolics from Mastocarpus stellatus Using Pressurized Green Solvents

Polyunsaturated fatty acids are well known for their protective properties in relation to different skin diseases. Although seaweeds possess a low lipid fraction, they could act as an alternative renewable source of polyunsaturated fatty acids whenever other valuable seaweed components are also valorized. In this study, a biorefinery process using Mastocarpus stellatus as a model seaweed was proposed. The process started with the supercritical carbon dioxide extraction of the lipid and phenolic fractions. The influence of pressure during extraction with pure supercritical CO₂ was studied while operating at a selected temperature and solvent flow rate. Kinetic data obtained during the ethanol-modified supercritical CO₂ extraction were fitted to the spline model. Sequential processing was proposed with (i) pure CO₂ to obtain a product with 30% PUFA content and ω-3:ω-6 ratio 1:1, (ii) ethanol-modified CO₂ to extract phenolics, and (iii) microwave-assisted subcritical water extraction operating under previously optimized conditions for the extraction of phenolics, carrageenan and protein fractions. The composition of the supercritical extracts showed potential for use in both dietary and topical applications in skin care products. The remaining solids are suitable for the extraction of other valuable fractions.

Optimization of Extraction Conditions for Gracilaria gracilis Extracts and Their Antioxidative Stability as Part of Microfiber Food Coating Additives

Incorporation of antioxidant agents in edible films and packages often relies in the usage of essential oils and other concentrated hydrophobic liquids, with reliable increases in antimicrobial and antioxidant activities of the overall composite, but with less desirable synthetic sources and extraction methods. Hydroethanolic extracts of commercially-available red macroalgae Gracilaria gracilis were evaluated for their antioxidant potential and phenolic content, as part of the selection of algal biomass for the enrichment of thermoplastic film coatings. The extracts were obtained through use of solid-liquid extractions, over which yield, DPPH radical reduction capacity, total phenolic content, and FRAP activity assays were measured. Solid-to-liquid ratio, extraction time, and ethanol percentages were selected as independent variables, and response surface methodology (RSM) was then used to estimate the effect of each extraction condition on the tested bioactivities. These extracts were electrospun into polypropylene films and the antioxidant activity of these coatings was measured. Similar bioactivities were measured for both 100% ethanolic and aqueous extracts, revealing high viability in the application of both for antioxidant coating purposes, though activity losses as a result of the electrospinning process were above 60% in all cases.

Emerging Technologies for the Extraction of Marine Phenolics: Opportunities and Challenges

Natural phenolic compounds are important classes of plant, microorganism, and algal secondary metabolites. They have well-documented beneficial biological activities. The marine environment is less explored than other environments but have huge potential for the discovery of new unique compounds with potential applications in, e.g., food, cosmetics, and pharmaceutical industries. To survive in a very harsh and challenging environment, marine organisms like several seaweed (macroalgae) species produce and accumulate several secondary metabolites, including marine phenolics in the cells. Traditionally, these compounds were extracted from their sample matrix using organic solvents. This conventional extraction method had several drawbacks such as a long extraction time, low extraction yield, co-extraction of other compounds, and usage of a huge volume of one or more organic solvents, which consequently results in environmental pollution. To mitigate these drawbacks, newly emerging technologies, such as enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE) have received huge interest from researchers around the world. Therefore, in this review, the most recent and emerging technologies are discussed for the extraction of marine phenolic compounds of interest for their antioxidant and other bioactivity in, e.g., cosmetic and food industry. Moreover, the opportunities and the bottleneck for upscaling of these technologies are also presented.

Seaweed Phenolics: From Extraction to Applications

Seaweeds have attracted high interest in recent years due to their chemical and bioactive properties to find new molecules with valuable applications for humankind. Phenolic compounds are the group of metabolites with the most structural variation and the highest content in seaweeds. The most researched seaweed polyphenol class is the phlorotannins, which are specifically synthesized by brown seaweeds, but there are other polyphenolic compounds, such as bromophenols, flavonoids, phenolic terpenoids, and mycosporine-like amino acids. The compounds already discovered and characterized demonstrate a full range of bioactivities and potential future applications in various industrial sectors. This review focuses on the extraction, purification, and future applications of seaweed phenolic compounds based on the bioactive properties described in the literature. It also intends to provide a comprehensive insight into the phenolic compounds in seaweed.

Integral Utilization of Red Seaweed for Bioactive Production

The hydrocolloids carrageenan and agar are the major fraction industrially extracted and commercialized from red seaweeds. However, this type of macroalgae also contains a variety of components with nutritional, functional and biological properties. In the context of sustainability and bioeconomy, where the integral utilization of the natural resources is incentivized, the sequential separation and valorization of seaweed components with biological properties of interest for food, nutraceuticals, cosmeceuticals and pharmaceuticals is proposed. In this work, a review of the available conventional and alternative greener and efficient extraction for obtaining red seaweed bioactives is presented. The potential of emerging technologies for the production of valuable oligomers from carrageenan and agar is also commented, and finally, the sequential extraction of the constituent fractions is discussed.

Some Advances in Supercritical Fluid Extraction for Fuels, Bio-Materials and Purification

Supercritical fluids are used for the extraction of desired ingredients from natural materials, but also for the removal of undesired and harmful ingredients. In this paper, the pertinent physical and chemical properties of supercritical water, methanol, ethanol, carbon dioxide, and their mixtures are provided. The methodologies used with supercritical fluid extraction are briefly dealt with. Advances in the application of supercritical extraction to fuels, the gaining of antioxidants and other useful items from biomass, the removal of undesired ingredients or contaminants, and the preparation of nanosized particles of drugs are described.

Overview on the Application of Modern Methods for the Extraction of Bioactive Compounds from Marine Macroalgae

Marine macroalgae represent a rich source of bioactive compounds that can be implemented in various food, cosmetic, and pharmaceutical products for health improvement. It has been proven that these bioactive compounds, such as polyphenols, polysaccharides, carotenoids, and ω-3 fatty acids possess bioactivity. For the extraction of these compounds, modern methods (Supercritical Fluid Extraction (SFE), Subcritical Water Extraction (SWE), Ultrasound-Assisted Extraction (UAE), and Microwave-Assisted Extraction (MAE)) have been used due to their advantages over the conventional methods. The process parameters of each method must be optimized for obtaining the extracts with the targeted bioactive compounds. In distinction from the existing reviews, the present review provides novelty with respect to: (a) presenting systematically the selected process parameters of SFE (temperature, time, pressure, use of co-solvents), SWE (temperature, time, pressure, solid-solvent ratio), UAE (temperature, time, frequency, power, solid-solvent ratio), and MAE (temperature, time, frequency, power, solvent type) applied for the extractions of marine macroalgae; (b) reporting the major groups or individual compounds extracted with their biological activities (if determined); and, (c) updating available references.